Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, a generator, a gearbox, a nacelle, and one or more rotor blades. The nacelle includes a rotor coupled to the gearbox and to the generator. The rotor includes a rotatable hub having a plurality of rotor blades mounted thereto. The rotor and the gearbox are mounted on a bedplate member support frame located within the nacelle. More specifically, in many wind turbines, the gearbox is mounted to the bedplate member via one or more torque supports or arms. The rotor blades can be individually rotated or pitched about their respective pitch axes and the nacelle may be rotated about its yaw axis such that the rotor faces into the wind, thereby capturing more energy. As such, the rotor blades capture kinetic energy of wind using known airfoil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
Wind turbines may be placed individually or in groups, also known as wind farms, in on- or off-shore environments. When the wind turbine is placed in the proximity of a residential area, it is possible when the sun is in unfavorable positions, that the wind turbine or rotor thereof is between the sun and a residence of the residential area. If the sunshine is not affected by dark clouds, the rotating rotor constantly throws a shadow onto the residence or property thereof. The shadow casting, also known as shadow flicker, caused by a wind turbine on the adjoining properties is often perceived by the residents as being very troublesome and may spook animals, such as animals grazing in the proximity of a wind turbine.
Several factors, such as the position and point of the sun and cloudiness, may influence the shadow flicker behavior of wind turbines. In the northern hemisphere, the risk for shadow flickering is largest in spring, autumn and winter as well as sunrise and sunset. Therefore, even if the wind turbine satisfies the legal approval requirements, there is no guarantee that the undesired shadow casting effect is prevented.
The effect of shadow flicker may be resolved via wind turbine shut-down systems that use a plurality of light sensitive sensors typically positioned in different locations to determine the shadow casting behavior of a wind turbine. More specifically, the light sensors are used to determine light intensity at different regions, i.e., in a shadowed region and in a light region with direct light incidence (direct sun irradiation). Such shut-down systems often have a complex set-up and wiring and each light sensitive sensor is prone to failure. Accordingly, if one of the light sensors fails, the shut-down system fails, thereby causing the shut-down systems to be unreliable.
In view of the foregoing, a system and method for managing wind turbine shadow flicker that addresses the aforementioned issues would be welcomed in the art.